Three flaws in the Apple Watch heart health study

Digging into the details of the Stanford study shows that digital clinical trials have some of the same problems that traditional studies do.

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Tim Cook is placing a big bet on health. He wants Apple to be known for making people healthier as much as making people buy AirPods. Researchers from the Stanford School of Medicine launched the Apple Heart Study using the Apple Watch in 2017 and enrolled over 400,000 people. Apple released initial results in March, showing that 2,161 people got an alert about an irregular pulse— 0.52% of the total. 

Stanford researchers just published a paper in the New England Journal of Medicine about the Apple project, “Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation.”

Researchers concluded that the Watch is pretty good at detecting irregular heart beat, which is a significant advance in medical technology. That’s great for people who have their own Apple Watch as well as the people who can get a watch through their Medicare plan

The study also highlights the limitations of using the Watch for clinical trials. Researchers relying on the Watch to notice health problems face some of the same limitations traditional researchers. Here are three flaws found in the virtual health study that Apple should fix next time around.

Wrong demographic

About half of the people in the study were under 40. Only 6% were over 65. Atrial fibrillation is most common in people over 65, meaning this study may be “the opposite of a desirable age profile for a study of atrial fibrillation,” as Edward W. Campion, M.D., and John A. Jarcho, M.D. wrote in an editorial about the research…